First 'rule' of evolution suggests that life is destined to become more complex

Mar 17, 2008

Scientists have revealed what may well be the first pervasive ‘rule’ of evolution. In a study published in the Proceedings of the National Academy of Sciences researchers have found evidence which suggests that evolution drives animals to become increasingly more complex.

Looking back through the last 550 million years of the fossil catalogue to the present day, the team investigated the different evolutionary branches of the crustacean family tree.

They were seeking examples along the tree where animals evolved that were simpler than their ancestors.

Instead they found organisms with increasingly more complex structures and features, suggesting that there is some mechanism driving change in this direction.

“If you start with the simplest possible animal body, then there’s only one direction to evolve in – you have to become more complex,” said Dr Matthew Wills from the Department of Biology & Biochemistry at the University of Bath who worked with colleagues Sarah Adamowicz from from the University of Waterloo (Canada) and Andy Purvis from Imperial College London.

“Sooner or later, however, you reach a level of complexity where it’s possible to go backwards and become simpler again.

“What’s astonishing is that hardly any crustaceans have taken this backwards route.

“Instead, almost all branches have evolved in the same direction, becoming more complex in parallel.

“This is the nearest thing to a pervasive evolutionary rule that’s been found.

“Of course, there are exceptions within the crustacean family tree, but most of these are parasites, or animals living in remote habitats such as isolated marine caves.

“For those free-living animals in the ‘rat-race’ of evolution, it seems that competition may be the driving force behind the trend.

“What’s new about our results is that they show us how this increase in complexity has occurred.

“Strikingly, it looks far more like a disciplined march than a milling crowd.”

Dr Adamowicz said: “Previous researchers noticed increasing morphological complexity in the fossil record, but this pattern can occur due to the chance origination of a few new types of animals.

“Our study uses information about the inter-relatedness of different animal groups – the ‘Tree of Life’ – to demonstrate that complexity has evolved numerous times independently.”

Like all arthropods, crustaceans’ bodies are built up of repeating segments. In the simplest crustaceans, the segments are quite similar - one after the other. In the most complex, such as shrimps and lobsters, almost every segment is different, bearing antennae, jaws, claws, walking legs, paddles and gills.

The American biologist Leigh Van Valen coined the phrase ‘Red Queen’ for the evolutionary arms race phenomenon. In Through the Looking-Glass Lewis Carroll’s Red Queen advises Alice that: “It takes all the running you can do, to keep in the same place.”

“Those crustacean groups going extinct tended to be less complex than the others around at the time,” said Dr Wills.

“There’s even a link between average complexity within a group and the number of species alive today.

“All organisms have a common ancestor, so that every living species is part of a giant family tree of life.”

Dr Adamowicz added: “With a few exceptions, once branches of the tree have separated they continue to evolve independently.

“Looking at many independent branches is similar to viewing multiple repeated runs of the tape of evolution.

“Our results apply to a group of animals with bodies made of repeated units. We must not forget that bacteria – very simple organisms – are among the most successful living things. Therefore, the trend towards complexity is compelling but does not describe the history of all life.”

Relevant PhysicsForums posts

Related Stories

The ancestors of a large family of parasites—including those that cause malaria—were equipped to become parasites much earlier in their lineage than previously assumed, according to University of British Columbia (UBC) ...

(Millbrook, NY) In the northeastern United States, warmer spring temperatures are leading to shifts in the emergence of the blacklegged ticks that carry Lyme disease and other tick-borne pathogens. At the ...

A revolutionary new £1M laser instrument in the UK is set to illuminate the innermost workings of DNA, protein, enzyme and other molecules that play a critical role in key natural processes in humans, animals ...

Aircraft designers and animators use different digital technologies to achieve the same goal: creating a three-dimensional image that can be manipulated. But a new method that links the two could vastly speed ...

Recommended for you

UCLA life scientists have created an accurate new method to identify genetic markers for many diseases—a significant step toward a new era of personalized medicine, tailored to each person's DNA and RNA.

While studying a ground-nesting bird population near El Reno, Okla., a University of Oklahoma-led research team found that stress during a severe weather outbreak of May 31, 2013, had manifested itself into malformations ...

(Phys.org)—There is no mistaking the first action potential you ever fired. It was the one that blocked all the other sperm from stealing your egg. After that, your spikes only got more interesting. Waves ...

The robust advances in pain management for companion animals underlie the decision of the American Animal Hospital Association (AAHA) and the American Association of Feline Practitioners (AAFP) to expand on the information ...

(Phys.org)—A pair of researchers with Harvard University has uncovered one of the secrets behind pigeons' impressive flight abilities. In their paper published in Proceedings of the National Academy of ...

User comments : 7

Rediculous. It is obvious that simple living things have a tendency to become more complex in order th take advantage of their niches and to adapt to new ones. There are plenty of examples of simplification. - Vestigial limbs, appendix, cave fish with no or insignificant eyes.

Leverage this concept to economics and you have comparative advantage. Fewer specialized cells can perform the function better than more generalized cells. Fewer specialized workers in an economy are more efficient that more generalized ones.

What are you counting or measuring to
derive complexity?
In what environment? All?

A more fundamental statement would be
that a change in environment drives a
response which is met with (easiest to
more difficult)
1) change to existing system, or
2) addition to existing system, or
3) reduction in system.

Your statement is a specific example of
a theorm already published by Godel.

Please look at following link.
http://www.edinfo...odel.htmExtract:
"Kurt Gödel (April 28, 1906 - January 14, 1978) was a mathematician whose biography lists quite a few nations, although he is usually associated with Austria. He was born in Austria-Hungary (which broke up after World War I), became Czechoslovak citizen at age 12, and Austrian citizen at age 23. When Austrian-born Hitler annexed Austria, Gödel automatically became German at age 32. After WW-II, at age 42, he also obtained US citizenship in addition to his Austrian one.

He was a deep logician whose most famous work was the Incompleteness Theorem stating that any self-consistent axiomatic system powerful enough to describe integer arithmetic will allow for propositions about integers that can neither be proven nor disproven from the axioms. He also produced celebrated work on the Continuum hypothesis, showing that it cannot be disproven from the accepted set theory axioms, assuming that those axioms are consistent. Also of note is Gödel's ontological proof, a formalization of St. Anselm's ontological argument for God's existence.

Arguably, Kurt Gödel is the greatest logician of the 20th century and one of the three greatest logicians of all time, with the other two of this historical triumvirate being Aristotle and Frege. He published his most important result in 1931 at age 25 when he worked at Vienna University, Austria. "

ALSO;
Since any response to a change in
environment, other than no reaction,
changes that environment; a change race
or "arms race" results. That is until
the system complexity exceeds functional
reproducibility, then mal-function results.

At that point increasing complexity is
more likely to result in mal-funtion than
improved function. (see FAA report on
result of improvements to airlines.)

I like the ideas of both marjon and AJW (I suppose Kurt Godel, really).

Regarding AJW's comments:I agree and think it's intuitive that environmental conditions dictate whether a simpler or more complex change is more beneficial.

If, for instance, your environment favors those with more appendages, then more appendages will give you an evolutionary advantage, allowing that mutation to increase in number. If, however, the environment begins to start favoring vines (for example), those with more appendages may get caught in them, which causes a disadvantage. Therefore, those with fewer appendages have the advantage, moving then towards simplicity.

Marjon's comment about specialized cells always beating general cells makes sense to a point. In a company, doesn't a skilled specialist perform better in their area of expertise than a generalist? However, the company has to pay for that specialty. A company will not take on a whole workforce of specialists, because they would need to pay too much money. Likewise, in the evolutionary process, specialized cells will perform better in their immediate context. Eventually, the cost of the specialization to the organism as a whole will cost it too much in terms of energy and cooperation amongst the specialists who are all vying for resources. So specialization will also have it's limits.

I would summarize it, then, like this:Movement in evolution will be toward complexity, limited by environmental conditions and cost to the host organism.

The new analysis also indicates that viruses emerged not long after the archaea, with the superkingdoms eukarya and bacteria following much later %u2013 and in that order. This finding may influence the ongoing debate over whether viruses existed prior to, or after, the emergence of living cells, Caetano-Anolles said.

B. From ttp://genomebiology.com/2000/1/3/reviews/1020/

Archaea (as exemplified by Pyrococcus sp.) replicate their circular genome from a single DNA replication origin as do bacteria, even though they may use eukaryotic-like proteins to do so. This single-origin replication is unlike human's, as our DNA replication depends on initiation at thousands of different origins. The multiple sites of initiation are essential for timely replication of large eukaryotic genomes. The archaebacterial Pyrococcus genomes by contrast are smaller even than that of Escherichia coli, so perhaps we should not be surprised that archaea can replicate like E. coli using a single origin.

Evolution is always in the direction of more effective survivability; however, this is not always in the direction of more complexing for coping with changing environments and competition. In a stable nutritious environment, like in Earth's oceans, coping with vital requirenments, evolution, is in the opposite direction, simplify tooling and means.

It is plain common sense that viruses, even Viroids and Virusoids, nothing more than single strands of DNA or RNA, sometimes only 200-300 nucleotides long, are organisms as alive as we are, evolved at life genesis era and selected for survival in forms, composition and capabilities by living, and even replicating, off their richer kin. Smart little buggers.

- Earth Life Is A Real Virtual Affair; it pops in and out of existence in its matrix, which is the energy constrained in Earth's biosphere .

- Genes are organisms, interdependent members of genes communes, genomes, all continuously undergoing evolution directed towards survival as long as possible, for maintaining Earth's biosphere as long as possible.

- Culture is a ubiquitous biological entity and is the major effector of genetic evolution, of capabilities and attributes selected for survival.

- The major course of natural selection is not via random mutations followed by survival, but via interdependent, interactive and interenhencing selection of biased replication routes by genes at their alternative-splicing-steps junctions, effected by the cultural feedback of the second stratum multicells organism or monocells community to their prime stratum genes-genome organisms.

- Evolution of life is but a minute component of the evolution of the universe. Cosmic evolution is the evolution of energy. Life, like all objects and processes and natural laws in the universe, are - since none in exsistence at singularity - products of evolution and are continuously further evolving. Everything in the cosmos is fractal, rehappens on many scales, and is continuously evolving. Each and every system in the universe continuously evolves within the total universal evolution and all the systems' evolutions are intertwined and within it life's evolution is the evolution of genes-genomes, in a losing attempt to survive, to maintain - as long as possible - pockets of constrained energy that would otherwise and anyhow eventually expand and dilute with the whole mass and energy of the cosmos...

Dov Henis

Puzzled why even Darwinians do not comprehend that Darwinism starts all the way back with Life's day one, with the pre-archaea not-yet-genomed-celled genes...

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.

Javascript is currently disabled in your web browser. For full site functionality, it is necessary to enable Javascript.
In order to enable it, please see these instructions.